1. Field of the Invention
The present invention relates to wrenches which automatically lock on an element to which torque is to be applied, that is, are self-adjusting, and more particularly to such wrenches which provide a ratcheting function when rotated in the direction opposite that rotational direction which applies torque to the element.
2. Summary of the Prior Art
Self-adjusting wrenches which provide a ratcheting function are well known in the art, and are shown, for example, in U.S. Pat. No. 2,645,145, issued Jul. 14, 1953 to J. V. Larson, in which the wrench has a fixed jaw and a movable jaw which is pivotally connected to the fixed jaw, the jaws being manually openable by pressing on a "trigger" formed as a tail portion of the movable jaw. However, the trigger is located at the end of the wrench handle closest to the wrench jaws, and so normally requires a change in the user's grip on the wrench handle to operate the trigger. The wrench shown in U.S. Pat. No. 4,651,597, issued Mar. 24, 1987 to T. Yang, attempts to overcome this difficulty by providing a slot in the tail portion of the movable jaw and a spring-biased control link within the handle portion of the wrench, the control link having a pin at one end which engages the slot so as to be manually operable to open the jaws. However, this design is somewhat bulky and difficult to manufacture, and has not found widespread use.